Event Abstract Back to Event Spatio-temporal structure of multi-focal magnetoencephalographic visual evoked potentials (MVEP). David P. Crewther1*, Alyse Brown1 and Laila Hugrass1 1 Swinburne University of Technology, Life and Social Sciences, Australia Nonlinearities of the VEP have provided useful insights into early cortical neural processing in normals and autism spectrum. Signatures for magnocellular and parvocellular processing have been based on contrast response function, saturation and latency of response peaks. We aimed to extend these studies to magnetoencephalography (MEG). Five participants observed a projected dartboard comprising 9 unstructured patches each executing pseudo-random binary m-sequences. Four minute recordings on the 306 sensor Elekta Triux system were made at Michelson contrasts of 24% and 95% (60 Hz frame rate). Wiener kernel kernel analysis of the first-order K1 and the first two slices of the second-order kernel (K2 .1 & K2 .2) were completed for the foveal patch. K1 was characterized by major peaks with latencies of 98 ms and 120 ms. K2 .1 was characterized by two early peaks (latencies 85 ms, 102 ms) while K2 .2 demonstrated peaks rather more delayed in latency. Initial estimates of contrast response were made by comparing the low and high contrast evoked responses. This comparison shows that the early peak of the first slice K2.1 was already quite large and measurable with 24% contrast (Fig 1) and did not grow much at higher contrasts, indicative of the likely magnocellular origin. The peaks of the second slice of the second order response, by comparison, grew significantly in amplitude were more complex in contrast response. This is the first report of nonlinear MEG, and points to reliable identification and location of magno and parvocellular processing in cognitive function. Figure 1 Acknowledgements NHMRC grant #1004740 Keywords: Magnocellular, Parvocellular, Magnetoencephalography, MEG, contrast response. Conference: ACNS-2012 Australasian Cognitive Neuroscience Conference, Brisbane, Australia, 29 Nov - 2 Dec, 2012. Presentation Type: Oral Presentation Topic: Sensation and Perception Citation: Crewther DP, Brown A and Hugrass L (2012). Spatio-temporal structure of multi-focal magnetoencephalographic visual evoked potentials (MVEP).. Conference Abstract: ACNS-2012 Australasian Cognitive Neuroscience Conference. doi: 10.3389/conf.fnhum.2012.208.00029 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Oct 2012; Published Online: 07 Nov 2012. * Correspondence: Prof. David P Crewther, Swinburne University of Technology, Life and Social Sciences, Hawthorn, VIC, 3122, Australia, dcrewther@swin.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers David P Crewther Alyse Brown Laila Hugrass Google David P Crewther Alyse Brown Laila Hugrass Google Scholar David P Crewther Alyse Brown Laila Hugrass PubMed David P Crewther Alyse Brown Laila Hugrass Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.